[InstCombine] propagate fast-math-flags when folding fcmp+fpext, part 2

llvm-svn: 346242

1 files changed, 6 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
index e8e78d2e652..62493decb4a 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -5483,9 +5483,12 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
       Fabs.clearSign();
       if (!Lossy &&
           ((Fabs.compare(APFloat::getSmallestNormalized(FPSem)) !=
-            APFloat::cmpLessThan) || Fabs.isZero()))
-        // TODO: Propagate FMF.
-        return new FCmpInst(Pred, X, ConstantFP::get(C->getContext(), F));
+            APFloat::cmpLessThan) || Fabs.isZero())) {
+        Instruction *NewFCmp =
+            new FCmpInst(Pred, X, ConstantFP::get(C->getContext(), F));
+        NewFCmp->copyFastMathFlags(&I);
+        return NewFCmp;
+      }
     }
   }